Blood thinners may raise stroke risk in over-65s with kidney disease

Older people may be increasing their stroke risk by taking anticoagulants for an irregular heartbeat if they also have chronic kidney disease, says new research.

15 February 2018

Researchers are warning doctors to be more cautious about prescribing anticoagulants, also known as blood thinners, to such patients until more studies can clarify the consequences of doing so.

The researchers, whose study is published in the BMJ, estimate that nearly half a million people over 65 in the UK have both chronic kidney disease and atrial fibrillation.

John Camm, Professor of Clinical Cardiology, St George’s, University of London, said: “People with chronic kidney disease tend to have numerous severe complications, including cardiovascular illnesses.

"As their blood clots more but they also bleed more easily, it is extremely difficult to strike a balance between different treatments."

"Until more data is available, general practitioners, nephrologists and cardiologists need to weigh up the risks and benefits of giving an anticoagulant and make a decision together with their patient" said co-author Professor David Goldsmith, of Guys and St Thomas’ Hospitals NHS Foundation Trust and St George’s, University of London.

In the study, the researchers used a Royal College of General Practitioners database to identify 4848 people over 65 with chronic kidney disease and newly diagnosed atrial fibrillation, half of whom were on anticoagulants and half were not. The participants were monitored for a median of 506 days.

Over the study period, participants who were taking anticoagulants were 2.6 times as likely to have a stroke, and 2.4 times as likely to have a haemorrhage.

Mortality in the anticoagulant group was slightly lower; the researchers speculate it may have been due to a reduced risk of fatal strokes or heart attacks, but they say that more research is needed.

"Chronic kidney disease is common among older people, and one in three people affected also have atrial fibrillation, commonly called an irregular heartbeat and for that, they typically get prescribed blood thinners to reduce their risk of stroke."

"We found that in this particular group, their medication seems to do the opposite of its intended effect" said the study’s first author, Dr Shankar Kumar, of UCL’s Centre for Medical Imaging.

The study was conducted by researchers at UCL, St George’s, University of London, the University of Surrey, Guys and St Thomas’ Hospitals NHS Foundation Trust and NYU School of Medicine, USA.